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Miko
2007.08.12, 01:58 PM
Does it matter if the motor wire side fet pins are soldered together or not? I mean 4 pins and 4 pins, not all 8 together.

Spoon
2007.08.12, 02:14 PM
It doesn't matter at all. The pins on the motor side can be soldered together. 4 and 4 like you said...

ub0211042
2007.08.12, 11:55 PM
It doesn't matter at all. The pins on the motor side can be soldered together. 4 and 4 like you said...

Hi Spoon,

Can u tell me what does this means? i got it from
http://mini-z.home.att.net/FETInstall.htm

"Before powering on for the first time, make sure you verify that all connections are solid. You can blow the FET if the gate connection to the P-Channel is not made when you turn on the power. You will create an instant short in that FET. P-channel depends on voltage to turn off, so if there is no connection, it is always turned on, and when the N-channel is turned on by the controller, then there would be a short. A quick way to check connection is to use an ohm meter with an alligator clip holding a pin. Place one pin on the FET, and another on the circuit board. Make sure there is continuity"

and how to check the connection according to what the text says?

Thanks!

ub0211042
2007.08.13, 12:12 AM
Hi Again,

by using multimeter i realized i'm having some continuity at the motor out put (ie. the +ve and -ve side). the reading was around 50 ohm (if i read it correctly).

Is this normal or might that be the cause that my Fet will just burn once the battery is put in and without turning on the switch. (or could the text i pasted above xplains this problem?)

My fet always burns on the P-Channel on the forward control fet side.

Aurora
2007.08.13, 02:18 AM
I think two of the possible issues of causing the short immediately, even before switch 'on' are:

1) there might be a twist or short for the on/off switch, so it is turned on all the time
2) there is a short for the motor wires or motor pad...either under or above the board. This problem should be easily detected with the continuity function on a multimeter.

ub0211042
2007.08.13, 03:49 AM
I think two of the possible issues of causing the short immediately, even before switch 'on' are:

1) there might be a twist or short for the on/off switch, so it is turned on all the time
2) there is a short for the motor wires or motor pad...either under or above the board. This problem should be easily detected with the continuity function on a multimeter.

hi aurora,

ermm there's no short on the on/off switch but there is some continuity between the +ve and -ve motor pad...

i check and the resistance is around 50 ohm... when i check with a stock un touched PCB, the motor pad doesn't have any continuity at all...

some of my other car that ive fetted before, there is some continuity at about 50 ohm also but so far no problem with it...

benmlee
2007.08.13, 01:15 PM
I just added a picture to the site on which contacts to check.

http://mini-z.home.att.net/FETInstall.htm

If other connection to the FET are not made, the car just won't run. If the P-channel is not connected, you can burn the fet.
Basically, there are 4 fets that control the car. Two for forward and two for reverse. The forward ones has to be turn off before the reverse goes on. If forward and reverse goes on at the same time, something will blow. You want to make sure the P channels are connected to the circuit board so the board can turn them off at the right time.

ub0211042
2007.08.13, 01:25 PM
I just added a picture to the site on which contacts to check.

http://mini-z.home.att.net/FETInstall.htm

If other connection to the FET are not made, the car just won't run. If the P-channel is not connected, you can burn the fet.
Basically, there are 4 fets that control the car. Two for forward and two for reverse. The forward ones has to be turn off before the reverse goes on. If forward and reverse goes on at the same time, something will blow. You want to make sure the P channels are connected to the circuit board so the board can turn them off at the right time.

Thanks so much for the pic...i will check my PCB tonite.
If the PCB already having this problem once...do u think the PCB is totally damaged?

BTW the steering still works fine.

ub0211042
2007.08.13, 02:51 PM
hi benmlee,

new things to share here, i try to put back in the 3004 fets onto the PCB and it works well...i try leaving the battery inside and switch off the car. After few minutes, the fet start burn by itself.

then i take out the battery, remove the burn fet and try putting the battery in with only 1 fet installed. The fet also starts to burn by itself.

something more weird happen is when i put in the battery again and switch the car on with only 1 fet installed...the steering works fine but when i turn off the car again, this time the fet doesn't burn but the steering starts to glitch by it self.

won't want to take any risk by letting the batteries inside the car much longer so i took the batteries out, affraid the whole PCB might burn up.

please help me find the answer